1. Field of the Invention
The present invention relates to a cognition device for battery residual capacity, especially useful for portable wireless equipment or office automation equipment.
2. Description of the Prior Art
Conventional cognition devices for battery residual capacity have used a device which directly measures the residual capacity or a device in which residual capacity is obtained from consumed electric power obtained by integrating current during the time which a battery is used with a timer.
In conventional cognition devices for battery residual capacity as described above, there has been a problem that battery residual capacity cannot be measured accurately due to changes in battery voltage resulting from changes in ambient temperature or load.
Japanese Patent Application laid-open No. 218077/85 describes a method of temperature correction for such a condition. In this method, a correction factor is calculated by using the temperature difference between the ambient reference temperature of 20.degree. C. and the ambient temperature at that time, but the correction for the temperature changes is too rough to obtain accurate residual capacity.